Operator product expansion and quark–hadron duality: facts and riddles
✍ Scribed by Ralf Hofmann
- Publisher
- Elsevier Science
- Year
- 2004
- Tongue
- English
- Weight
- 1017 KB
- Volume
- 52
- Category
- Article
- ISSN
- 0146-6410
No coin nor oath required. For personal study only.
✦ Synopsis
We review the status of the practical operator product expansion (OPE), when applied to twopoint correlators of QCD currents which interpolate to mesonic resonances, in view of the violations of local quark-hadron duality. Covered topics are: a mini-review of mesonic QCD sum rules in vacuum, at finite temperature, or at finite baryon density, a comparison of model calculations of current-current correlation functions in 2D and 4D with the OPE expressions, a discussion of meson distribution amplitudes in the light of nonperturbatively nonlocal modifications of the OPE, and a reorganization of the OPE which (partially) resums powers of covariant derivatives.